In the Feb. 16 SN: Robots roll into the classroom, brain zaps for severe depression, particle colliders of the future, how to walk like a tetrapod, sleepless nights boost Alzheimer's proteins and more.

Amphibian killer forces immune-cell suicides

Fungal menace shuts down key parts of defenses of frogs and their kin

AT RISK A poison dart frog (Dendrobates auratus) in Panama is just one of hundreds of amphibian species that succumbs to the chytrid skin fungus, which scientists now know has a special trick for disabling frog immune systems.

Courtesy of L.A. Rollins-Smith

A skin fungus that has swept around the globe killing frogs and their relatives can make key players in amphibian immune systems kill themselves.

The fungus nicknamed Bd (for Batrachochytrium dendrobatidis)has flummoxed biologists because the little skin bumps it causes in susceptible amphibians look inconsequential. Yet this member of the chytrid fungi can kill a wide range of animals, some within days.

Part of Bd’s power comes from compounds in its cell walls that disable amphibian immune cells called lymphocytes and trigger these cells to self-destruct, says Louise Rollins-Smith of Vanderbilt University in Nashville. These fungal substances can withstand heat, acid and a protein-smashing enzyme, Rollins-Smith and her colleagues report in the Oct. 18 Science.

Cells of many kinds carry built-in systems for do-it-yourself breakdown, known as apoptosis. Bd

This article is only available to Science News subscribers. Already a subscriber? Log in now. Or subscribe today for full access.